The KYB Gas-a-Just monotube shock absorber has additional performance advantages over the traditional twin-tube design: It can instantly, automatically adjust to your performance needs and never experiences fade due to aeration. The Gas-a-Just is available as an OE monotube replacement and as an OE twin-tube performance upgrade. The KYB Gas-a-Just has two separate working chambers: An air-free hydraulic piston and valve area for responsiveness & control, and a second high-pressure nitrogen gas area with a floating piston that provides a comfortable ride during normal driving and adds instant performance on demand. Provides up to 25% more damping control over original equipment shocks Gas-a-Just reacts to driving conditions and adds instant responsiveness High gas pressure design provides instant, extra control monotube design outperforms all other standard shock absorbers Unique, air-free, hydraulic unit eliminates performance fade